This application is to provide predoctoral fellowship support for training in the analytical chemistry, biochemistry, and pharmacology of the dopaminergic transporter. The research will focus on the outward functioning the dopamine transporter in striatal and nucleus accumbens tissues from the rat in vitro. The transporter kinetics will be measured by rotating disk electrode voltammetry. The goals are to define the multisubstrate mechanism of the outward functioning dopamine transporter, determine how it is influenced by direct application of drugs of abuse (cocaine and amphetamine), and investigate how withdrawal from repeated treatments with cocaine alters its outward function.